Twin centrifugal pump



March 30, 1954 w. SCHWEIZER TWIN CENTRIFUGAL PUMP 5 Shee'tS-Sheet l Filed April 9, 1951 ./NVENIOR:

IVI/sl March 30, 1954 w. SCHWEIZER 2,673,524 TWIN CENTRIFUGAL PUMP Filed April 9, 1951 3 Sheets-Sheet 2 March 30, 1954 W. SCHWEIZER TWIN CENTRIFUGAL PUMP 3 Sheets-Sheet 5 Filed April 9, 1951 INVENTOR! Patented Mar. 30, 1954 UN ITE D STATES PATEN T OFF I CE 2,673,524 TWIN CENTRIFUGAL PUMP Werner Schweizer, Bichwil, Switzerland Application April 9, 1951, Serial No. 219,959

Claims priority, application Switzerland December 15, 1950 My present invention relatesy to a twin centrifugal pump in which the impellersof both pumps are mounted on the ends ofV a common drive shaft, such as are known in the art for pumping liquid manure, dirty water and the like.

As disclosed by my present invention, the two pump casings, the drive-shaft bearings, and :i chest-shaped pedestal together form an integral block, which in its lower portion is bored to form a duct interconnecting the two pumps, with which passage is associated a detachable connecting pipe. By detaching the latter, access is afforded' to said passage and the pump interior for inspection andy service purposes.

Such block construction as rigid unit of a high strength, which safely withstands high pumping pressures and yet possesses a comparatively lowweight. A further advantage of my present invention is the fact that the liquid is moved through a minimum distance from the rst to the second pump, and that, by virtue of the detachability of the connecting pipe, the path of the liquid may be readily inspected.

A preferred form in the accompanying drawings, in which- Figs. la and lb together show an axial section of the twin centrifugal pump, and

Fig. 2 shows a cross-section on the line II-II of Fig. 1.

The rst-stage pump is designated by A, and the second-stage pump by B. The common drive shaft I which may be driven by any suitable drive means (not shown) connected intermediate its length, is provided at each end with two neck journals 2 and 3 carrying impellers 4 and 5 respectively. The shaft I at both end portions is shouldered in a plurality of steps for the purpose of improving the operating characteristics. The two impellers 4 and 5 which, as shown in Fig. 2, are formed in the manner of one-channel runners and will be more fully explained below, are symmetrically disposed relatively to the mid point of shaft I.

The two pumps A, B are interconnected by a casting C to form a unitary structure. For such purpose, the block C has an elongated upper connecting wall 6 which, together with two adjacent sidewalls 'I and two endwalls 8 and 9, respectively, forms the chest-like pedestal which is open at the bottom. Each of the two substantially similar casings of the pumps A, f B com prises a main portion vIIJ and Il respectively, which two mainportions form an integralst'ructure with the pedestal 1I-9. The said portions formation affords a very compact of my invention is shown iii) It and II comprise a plurality of stiffening ribs I2. i3 and a. detachable side cover I4 and I5 respectively. The casing of pump A has an upper filling cover I6 which is conically tapered (not shown in Fig. 2). A pipe bend il is detachably secured by clamping means (not shown) to the side cover UI of the casing of pump A, to which bend the suction pipe I8 is detachably secured. The numerals Iiiv and 20 designate the liquid chambers in the casings of the pumps A and B.

A pressure duct 2|v connects the pressure side of pump A to the suction side of pump B through an elbow 22. A pressure port 23 (shown by dashand-dot lines)` is integral with the casing of pump B. The said duct 2l is situated at the bottom of pedestal 6-9 and constitutes a component thereof and, thus, of the block C. A drain 2d is provided on the duct 2| and has a plug D associated therewith. The elbow 22 is secured by means of a stirrup which permits, i1" required, to detach the bend for inspection purposes.

Each impeller 4, 5 has an outlet 30 (Fig. 2) which interrupts the circumferential iange SI. The latter has a biconcave cross-section of which the inner side 32 faces the ribless impeller inside space, and the outer side 33 faces the pump chambers I9 and 20 respectively. The cross-section of these pump chambers also is rounded off, as shown in Fig. 1. The underside of cover IS is concave to nt the curvature of pump charnber I9.

By virtue of said construction of the impellers Il, 5 and chambers IS, 20 the two pumps are capable of handlingviscous liquids and liquids carrying foreign matter substantially without risk of blockage, whereby the eiiciency of the pump is improved.

The two pump-casing portions l5 and II which are disposed on top of the pedestal 6 9 and are integral with the block C, are formed as bearings fol the drive shaft I. For such purpose, a ball bearing 24 and 25 is provided in each casing portion I0 and II respectively. The numerals 26, 26a and 21, 27a designate stufing boxes of which the outside portions 26a, 2id are screwably engaged by a locking ring 2Gb and 2lb respectively, in order to permit to disassemble and replace the stuffing boxes. A ring 2B and 29 is disposed intermediate of each ball bearing and the appurtenant stuiiing box and is screwably engaged to the shaft I. The said rings on their free ends are stepped and have a circumferential flange in order to prevent the ball-bearing grease from leaving the bearing, and to prevent any stuing-box leakage from entering the ball bearing.

The diameter of the flange of the two rings 28, 29 is so chosen that the latter may be moved, together with shaft l or singly, from the pump operating chamber through the opening provided in the casing portions l0 and Il for the stuffing-box members 26a and 21a respectively. A stop ring 24a, 25a is associated with the ball bearings 24 and 25 respectively. The stop ring 24a is pinned to shaft I, whilst the stop ring 25a is screwed onto an auxiliary ring 25h which affords a conical seat to the ball bearing 25, whereby the latter may be axially adjusted. Caps 34, 35 are provided for the ball bearings 24 and 25 respectively.

The pressure port 23 provided on the pressure pump B may be laterally, i. e. axially disposed on the pump casing Il, instead of radially as shown, in order to permit to use the pump for stirring purposes and for connecting the same to pipe lines laid on the ground.

What I claim as new and desire to secure by Letters Patent, is:

A twin centrifugal pump comprising a unitary casting including a base having a duct therethrough and a centrifugal pump casing at each end thereof with one of said casings having a discharge opening in communication with one end of said duct, each said casing having a bearing in the respectively adjacent sides thereof and being open in the respectively opposite sides thereof, a shaft extending between said casings and journalled in said bearings with its ends disposed in the respective casings, said casings each including an inner wall defining the closed side of the pump chamber and an outer wall spaced from said inner wall forming said adjacent pump sides and supporting said shaft bearings, a liquid seal carried by said inner wall and surrounding the respective end portion of said shaft, a grease seal mounted on said shaft adjacent each said bearing and having a radial flange between said inner and outer walls for centrifugally throwing any liquid that might pass said grease seal, impellers insertable through the open sides of said casings and removably mounted on the respective shaft ends, said impellers comprising a radial web portion mounted on said shaft and an axially disposed substantially helical peripheral rim on said web portion and defning an open inlet side for said impeller opposite said web portion, the helically spaced ends of said rim defining the outlet for said impeller, uniform covers removably mounted on said casings and closing the open sides thereof, said covers having inlet openings substantially axially of said shaft, and inlet pipes removably connected to said covers and in communication with said openings, one said pipe comprising an elbow removably connected to said base and in communication with said duct to thereby place said pumps in series.

WERNER SCHWEIZER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 790,683 Harris May 23, 1905 2,190,670 Mann Feb. 20, 1940 2,266,107 Waterfill Dec. 16, 1941 FOREIGN PATENTS Number Country Date 94,909 Switzerland June 1, 1922 97,926 Switzerland Sept. 7, 1921 188,547 Great Britain Nov. 16, 1922 484,402 France July 9, 1917 

